Note: Descriptions are shown in the official language in which they were submitted.
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SHAFT FURNACE CHARGING DEVICE EQUIPPED WITH A COOLING
SYSTEM AND ANNULAR SWIVEL JOINT THEREFOR
Technical field
[0001] The present invention generally relates to a rotary charging device for
s charging a metallurgical reactor, in particular a shaft furnace, such as a
metallurgical blast furnace. Such a charging device usually comprises a
suspension rotor with a charge distributor, typically a pivotable distribution
chute,
and a stationary housing supporting the suspension rotor so that the rotor -
and
therewith the distributor - can rotate about an axis, which is typically the
furnace
central axis. The present invention relates more particularly to a cooling
system
configured to warrant cooling on the suspension rotor using an annular swivel
joint
for coupling a stationary portion of the cooling system to a rotary portion
that is
arranged on the suspension rotor. The invention also relates to the proposed
annular swivel joint itself (per se).
Background art
[0002] It is well known in the art that cooling the suspension rotor, which is
exposed to high internal furnace temperatures, by means of liquid coolant is
most
effective in extending the service life of mechanical components, has a lower
initial
investment cost and is less energy-consuming, when compared to pure inert gas
cooling as suggested e.g. in Japanese patent application JP 55 021 577.
[0003] Therefore, as early as 1978, PAUL WURTH proposed water cooling of
the charging device of a BELL LESS TOPS installation, as described in detail
in
US patent 4.273.492 (see FIG.8 of this patent). In this device, a lower
screen,
which protects against radiant heat from inside the furnace, has an associated
cooling circuit, which is supplied with liquid coolant via an annular swivel
joint
arranged coaxially around the central feed channel above the distribution
chute.
This joint comprises a rotating and a fixed part, which are generally annular
i.e.
ring-shaped. The rotary part is an extension of the suspension rotor and forms
an
integral part thereof that extends above the housing. The fixed part is
fastened to
the housing with a clearance coaxially around the rotary part. Two cylindrical
roller
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bearings centre the rotary part in the fixed part. The fixed part comprises
two
annular grooves, one above the other, which face ports in the external
cylindrical
surface of the rotary part to define connection passages for coolant.
Watertight
seal packings or gaskets have to be mounted to both sides of each groove in
between the fixed and rotary parts. In practice a revolving fluid joint of
this kind has
not proven successful. Indeed, the watertight seals as suggested in US
4.273.492
deteriorate rapidly, among others because they are in contact with a very hot
moving part. Moreover, due to the relatively large diameter of the revolving
joint
and consequently of the watertight seals, considerable friction is inevitable.
This
limits the service-life of the seals and, besides, also increases required
driving
power for driving the rotor. Accordingly, a rotating joint of the type
described in
US 4.273.492 has not proven practically viable for feeding a cooling circuit
portion
on the suspension rotor.
[0004] Therefore, in 1982, PAUL WURTH proposed a cooling system with a
revolving joint that works without any watertight seal packings or gaskets.
This
cooling system, as described in US patent 4.526.536, now equips numerous blast
furnace charging devices throughout the world. It includes an upper annular
trough, i.e. a narrow upwardly open receptacle, which is mounted on an upper
sleeve of the suspension rotor to rotate therewith. The stationary circuit
portion
has one or more ports above the upper trough for feeding the latter by
gravity. The
upper trough is connected to a number of cooling coils installed on the
suspension
rotor. These coils have outlet pipes discharging into a lower annular fixed
trough
that is mounted on the bottom of the housing. Cooling water therefore flows
from a
non-rotating supply into the rotary upper trough of the suspension rotor, then
passes purely by gravity trough the cooling coils on the rotor, and from there
into
the fixed lower trough from where it is discharged. Whilst having the major
benefit
of avoiding wear-prone watertight seals, a first disadvantage of this cooling
system
is that pressure available to force cooling water through the cooling coils on
the
suspension rotor is limited by the difference in height between the upper and
lower
troughs, which height in turn is inherently limited by constructional
constraints. The
suspension rotor must therefore be fitted with low-loss cooling coils, which
is a
considerable disadvantage in terms of cost, occupied space and/or cooling
efficiency. A second disadvantage is that dust-laden gases from the blast
furnace
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come into contact with the cooling water in both troughs so that dust
inevitably
passes into the cooling water. A particular problem is caused by the resulting
sludge formed in the upper trough, because the latter passes through the
cooling
coils of the suspension rotor and may cause blocking i.e. plugging of the
coils.
[0005] To achieve higher cooling capacity, German patent application
DE 33 42 572 proposes to fit the rotary circuit portions on the rotor with an
auxiliary pump. This auxiliary pump on the suspension rotor is driven by a
mechanism which takes advantage of the rotation of the rotor to drive the
pump. It
follows that the pump only works when the rotor is rotating. Moreover, such a
pump is rather sensitive to sludge passing through the cooling coils on the
rotor.
[0006] International patent application WO 99/28510 by PAUL WURTH presents
a method for operating a cooling system fitted with an annular swivel joint.
Contrary to previous principles, no attempt is made to ensure that the joint
is
watertight, as proposed by US 4.273.492 for example, nor to avoid coolant loss
from the joint by means of level controls, as specified in US 4.526.536.
Instead, a
supply of liquid coolant is provided to the annular swivel joint in such a way
that a
leakage flow passes through annular separation apertures between the rotating
and fixed parts of the joint. This leakage flow forms a "liquid seal", which
prevents
dust penetrating into the joint. The leakage flow is then collected and
drained,
without passing through the rotary portion of the circuit. Accordingly, dust-
laden
sludge no longer passes through the rotary circuit portion so that the risk of
clogging is eliminated. W099/28510 proposes a number of embodiments for
putting into practice the suggested method. Each embodiment comprises an
annular fixed part mounted on the stationary housing and an annular rotary
part
mounted on the suspension rotor. The parts have mating configurations that
allow
relative rotation. The rotary part, similar to the teaching of US 4.526.536,
includes
an annular trough that defines an annular volume, via which the stationary and
rotary circuit portions are in fluidal communication. The leakage flow passes
through annular separation apertures between sidewalls of the trough and
sidewalls of an insert that protrudes into the trough and belongs to the fixed
part. A
first drawback of this system is the loss of cooling water through the "liquid
seal",
which requires constant topping-up. Furthermore, the system and method
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proposed in WO 99/28510 still comes with a lower collecting trough (see FIG.1
of
WO 99/28510), similar to that proposed in US 4.526.536, and thus involves
additional dust contamination at this level. The lost water fraction and the
fraction
recovered from the lower trough thus both require treatment before reuse.
[0007] International patent application WO 03/002770 by PAUL WURTH
presents a further configuration of an annular swivel joint. This joint
partially
reverts to the initial principles of 1978 since it does not use open
collecting troughs
connecting the stationary and rotary circuit portions and thereby prevents
dust
contamination. It comprises a ring-shaped fixed part mounted to the housing
and a
ring-shaped rotary part rotating with the suspension rotor. The fixed and
rotary
parts together form a cylindrical interface in which one or more annular
grooves
allow transferring pressurized liquid coolant between the fixed and rotating
rings.
To this effect, watertight seals are provided in between the grooves and
between
the grooves and the open ends of the interface. The rotary part is supported
in
floating manner solely on the fixed part by means of roller bearings.
Selective
mechanical coupling means connect the ring-shaped rotary part with the
suspension rotor so as to transmit only rotational torque, while at the same
time
preventing other forces from being transmitted from the rotor to the rotary
ring.
Liquid coolant is transferred from the rotary part to the circuit portion on
the
suspension rotor by means of a deformable flexible connection. In the design
of
WO 03/002770, as opposed to that of US 4.273.492, the rotary ring is supported
by the fixed ring. Therefore, the joint in general, and the watertight seals
more
specifically, are less subject to problems of excessive friction and hence of
short
service-life. Whilst having the advantages of allowing pressurized forced
circulation through cooling coils on the rotor and of significantly increasing
the seal
service-live, watertight seals arranged between the fixed and rotary ring-
shaped
parts are still required. Even though subjected to reduced strain, these seals
will
unavoidably wear-off so that a costly replacement operation is inevitable.
[0008] International patent application WO 2007/071469 by PAUL WURTH
proposes another joint design for a cooling system as generally set out above.
In
the latter design, a heat transfer device includes a stationary part
configured to be
cooled by a cooling fluid flowing through a stationary cooling circuit and a
rotary
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part configured to be heated by separate cooling fluid circulated in the
rotary
cooling circuit. The parts are arranged in facing relationship and have there
between a heat transfer region for achieving heat transfer through the heat
transfer region without mixing of the separate cooling fluids in the rotary
and
5 stationary circuits. Accordingly, this revolving coupling is not a true
fluidal swivel
joint but rather a purely thermal coupling. Whilst a thermal coupling
according to
VVO 2007/071469 eliminates both the need for watertight seals and the risk of
dust
contamination altogether, one drawback of this coupling is that it requires a
certain
size of facing surfaces forming the heat transfer region in order to warrant a
given
thermal coupling capacity. In practice, when compared to fluidal swivel
joints, this
design thus requires more constructional space in case of high thermal loads,
e.g.
with large diameter blast furnaces. Moreover, means for forced circulation on
the
suspension rotor, e.g. a pump as disclosed in DE 33 42 572, are required when
using conventional cooling coils on the rotor.
[0009] In conclusion, although a variety of approaches are known today, the
prior art still leaves room for improving the swivel joint required to couple
the fixed
portion of the cooling system to the rotating portion.
Technical problem
[0010] It is therefore a first object of the present invention to provide an
zo improved cooling system for a shaft furnace charging device and more
specifically,
an improved annular swivel joint therefor, which eliminates the need of using
fluid
tight seals while at the same time enabling a pressurized forced circulation
of
cooling fluid through the rotary part of the cooling system.
[0011] This object is achieved by a shaft furnace charging device and by an
annular swivel joint as described below.
General description of the invention
[0012] The present invention generally relates to a cooling system in a
charging
device for a metallurgical reactor such as a shaft furnace, especially a blast
furnace. The device comprises, in typical manner, a suspension rotor with a
charge distributor, e.g. a pivotable chute, and a stationary housing, which
supports
the suspension rotor so that the latter is rotatable about an axis.
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[0013] The cooling system comprises a stationary circuit portion, which
remains
at rest with the housing and a rotary circuit portion that is arranged on the
suspension rotor to rotate with the latter. Furthermore, the cooling system
comprises an annular swivel joint, which is arranged coaxially on the rotation
axis
and connects the stationary circuit portion with the rotary circuit portion.
In the
present context, the expression "swivel joint" refers to a fluid-communicating
connector that permits full rotations between the connected circuit portions.
In a
manner known per se, e.g. from patent application WO 99/28510, the
fluidal/hydraulic swivel joint comprises a fixed part supported by the housing
and a
rotary part mounted on the suspension rotor. The parts have conjugated
configurations that allow relative rotation and either one of them includes an
annular trough that defines an annular volume, through which cooling fluid can
pass from one circuit portion to the other.
[0014] According to the presently claimed invention and in order to achieve
the
above-mentioned first object, the proposed fluidal/hydraulic swivel joint
presents
the following main features:
- at least four connections, including a pair of a forward and a return
connection to the stationary circuit portion, and a pair of a forward and a
return connection to the rotary circuit portion;
- a partition structure that divides the volume inside the annular trough into
an annular external cavity and an annular internal cavity in such a way that
the internal cavity is at least partly surrounded by the external cavity and
so
that the forward path passes through the internal cavity and the return path
passes through the external cavity or vice-versa;
- two flow restrictors, each arranged in one of two clearances, through which
the two separate cavities communicate and which are provided between the
fixed and rotary parts of the joint to allow relative rotation.
[0015] As will be appreciated, the proposed fluidal/hydraulic swivel joint is
configured so that cooling fluid can circulate in forced circulation from the
stationary circuit portion, through one of the first and the second cavities,
to the
rotary circuit portion and, through the other of the first and the second
cavities,
back to the stationary circuit portion.
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[0016] While providing dual coupling of both the forward and return paths and
even as it enables forced circulation, the proposed swivel joint is not based
on a
side-by-side arrangement to achieve the dual coupling nor does it require
liquid-
tight seals to enable forced circulation through the rotary circuit portion.
In fact,
both rotary-stationary interfaces on the forward side and on the return side
are
configured as open connections devoid of liquid-tight seals. More notably
however,
by virtue of the partition structure according to the invention, the proposed
joint
integrates one of both open connections to its counterpart i.e. "inside" the
other
open connection. Thereby, the circuit is truly "open" to the ambient
atmosphere
only at one of both connections, i.e. at one specific pressure potential of
the circuit.
Having a circuit open only at one specific pressure potential, the system can
provide forced circulation through any kind of rotary circuit, even high-
pressure
loss circuits, without the need for any wear-prone liquid-tight seal. All that
is
required is maintaining a pressure differential between the cavities. To this
effect,
any suitable kind of flow restrictors can be used, such as non-contact
labyrinth
seals. As another benefit compared to the widespread design of US patent
4.526.536 it will be noted that the need for a lower collecting trough is
eliminated,
where most of the dust contamination of the coolant water occurs in the
conventional prior art design. Accordingly, construction of the charging
device
itself can be simplified and, moreover, hitherto provided filtering devices
may
become unnecessary. This is achieved because the proposed swivel joint
functions as a dual coupling of for both paths, i.e. forward and return, and -
by
virtue of its configuration - it has much less exposed water surface compared
to a
conventional design according to US 4.526.536.
[0017] The present invention also relates to the annular fluidal/hydraulic
annular
swivel joint itself (per se) of claim 14, for use as a retrofitting component
in existing
charging devices or for newly equipping other kinds of metallurgical
installations or
metallurgical reactors, in which cooling of a rotating part of the
installation is
required. The proposed swivel joint can be used e.g. in the cooling system of
the
rabbling arms of a multiple hearth furnace. The swivel joint may, of course,
also
have any of the preferred features set out below when used independent of a
shaft
furnace charging device.
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[0018] In a preferred configuration, each of the first and second flow
restrictors is
respectively configured as non-contact labyrinth seal. In a simple
construction, the
partition is a multi-part structure that preferably comprises an annular
stationary
partition member supported by the stationary housing and an annular rotary
partition member supported by the suspension rotor. The internal cavity and
the
clearances can then defined in between and by the shape of the stationary and
rotary partition members. To achieve symmetrical pressure drop through both
restrictors, the stationary and rotary partition members are advantageously
configured generally mirror-symmetric with respect to a vertical bisecting
axis,
when seen in vertical cross-section. Similarly, the annular first clearance
and the
annular second clearance are beneficially generally mirror-symmetric with
respect
to a vertical axis with the annular first flow restrictor being a non-contact
labyrinth
seal arranged radially outward and the annular second flow restrittor being a
non-
contact labyrinth seal arranged radially inward. In order to provide
substantially
equal pressure drop, the difference in radius between the flow restrictors is
preferably taken into account and may be compensated e.g. by a difference in
effective flow restrictor length.
[0019] In a preferred and relatively simple construction of the swivel joint,
the
rotary part comprises the annular trough, which is mounted on or partially
formed
by the suspension rotor coaxially on the axis and is preferably of generally U-
shaped cross-section; and the fixed part comprises an annular hood, which is
mounted on the stationary housing so as to protrude at least partially into
the
trough and is preferably of generally inverted U-shaped cross-section. In this
construction, the trough and the hood are preferably also configured mirror-
symmetric with respect to a vertical bisecting axis.
[0020] In a particularly preferred embodiment, the stationary partition
comprises
a hood-shaped ring assembly, preferably of generally inverted U-shaped cross-
section, that is arranged inside the hood of the stationary part and has a
radially
inner side and a radially outer side. In this embodiment, the rotary partition
comprises at least one Teflon ring arranged to protrude into the ring
assembly,
the Teflon ring having a radially inner face and a radially outer face that
cooperate with the radially inner side and the radially outer side of the ring
assembly so as to provide the first and second clearance there between
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respectively and so as to form the first and second flow restrictors in the
clearances respectively. Teflon is preferred because of its resistance to
heat and
wetting and its wear-resistance (self-lubricating). In order to easily achieve
a
certain effective length of the flow restrictors, the swivel joint preferably
comprises
a plurality of stacked Teflon rings, each having a cross-section of a
truncated
wedge shape and/or corrugated inner and outer faces so as to form
comparatively
long first and second flow restrictors, e.g. of the labyrinth seal type.
[0021] When using a hood-and-trough configuration, the hood and the trough
preferably each have annular inner and outer sidewalls, the sidewalls of the
hood
being separated from the sidewalls of the trough by narrow substantially
vertical
gaps, which communicate freely through the external cavity. This configuration
minimizes the exposed water surface while also enabling an inherent venting
function with an appropriate forward/return connection scheme. To enhance
venting through the substantially vertical gaps, the vertical gaps preferably
communicate with the external cavity via transverse apertures provided in the
sidewalls of the hood or in between the annular hood and the stationary
partition
member.
[0022] In a simple manner of connecting the pairs of forward and return
connections, the stationary partition member comprises an upper plate, at
which
one of the stationary forward and the stationary return connections is
provided,
whereas the annular hood comprising a top plate, at which the other of the
stationary forward and the stationary return connections is provided.
Furthermore,
the rotary partition member comprises a lower plate, at which one of the
rotary
forward and the rotary return connections is provided, the annular trough
comprising a bottom plate, at which the other of the rotary forward and the
rotary
return connections is provided. In this configuration the external cavity
preferably
has an upper portion located between the upper plate and the top plate and a
lower portion located between the lower plate and the bottom plate.
[0023] Irrespective of the connecting scheme used, the external cavity
preferably substantially surrounds the internal cavity. Accordingly, the
external
cavity beneficially comprises an upper portion arranged above the internal
cavity
=
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and a lower portion arranged below the internal cavity, both portions
communicating, e.g. through the lateral gaps mentioned hereinabove.
[0024] As additional enhancements, the fixed part may comprise a coolant level
detection device that is connected to control a replenishing valve in the
stationary
5 circuit portion. Similarly, the fixed part preferably comprises a venting
device for
venting any gas inclusions, e.g. from the external cavity.
Brief description of the drawings
[0025] Preferred embodiments of the invention will now be described, by way of
example, with reference to the accompanying drawings in which:
10 FIG.1 is a partial vertical cross-sectional view of a charging device
equipped with a
cooling system and with an annular swivel joint according to a fist
embodiment;
FIG.2 is a schematic diagram of a simple first variant of a cooling system for
use
with the device of FIG.1;
FIG.3 is a view composed of a schematic diagram of a second variant of a
cooling
system for use with the device of FIG.1, including a venting device as shown
in
FIG.9, and an enlarged schematic vertical cross-sectional view of the annular
swivel joint of FIG.1;
FIG.4 is a perspective vertical section of the annular swivel joint of FIG.1;
FIG.5A is a top view of a second embodiment of an annular swivel joint;
FIG.5B is a bottom view of a second embodiment of an annular swivel joint;
FIG.6A is a vertical cross-sectional view of the second embodiment of an
annular
swivel joint according to lines A-A of FIG.5A;
FIG.6B is a vertical cross-sectional view of the second embodiment of an
annular
swivel joint according to lines B-B of FIG.5A;
FIG.6C is a vertical cross-sectional view of the second embodiment of an
annular
swivel joint according to lines C-C of FIG.5B;
F1G.6D is a vertical cross-sectional view of the second embodiment of an
annular
swivel joint according to lines D-D of FIG.5B;
F1G.7 is a perspective vertical section of the annular swivel joint of FIGS.6A-
C;
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FIG.8 is vertical cross-sectional view of an annular swivel joint according to
FIGS.1-4 illustrating a first embodiment of a venting device;
FIG.9 is vertical cross-sectional view of an annular swivel joint according to
FIGS.1-4 illustrating a second embodiment of a venting device;
FIG.10 is a vertical cross-sectional view of an annular swivel joint according
to a
third embodiment, which corresponds to a view taken along coinciding lines A-A
and C-C of FIGS.5A-B;
FIG.11 is a vertical cross-sectional view of an annular swivel joint according
to a
third embodiment, which corresponds to a view taken along coinciding lines B-B
and D-D of FIGS.5A-B;
FIG.12 is a vertical cross-sectional view of an annular swivel joint according
to a
fourth embodiment, which corresponds to a rotational position with coinciding
lines
B-B and D-D in FIGS.5A-B.
[0026] Identical reference signs or reference signs with incremented hundreds
digits are used to identify similar or identical parts throughout the
drawings.
Detailed description of preferred embodiments with respect to the drawings
[0027] FIG.1 partially illustrates a shaft-furnace-charging device, generally
identified by reference numeral 10. The charging device 10 is configured for
distributing bulk charge material (burden) in targeted manner into a blast
furnace.
The rotary charging device 10 is equipped with a cooling system 12,
illustrated in
FIGS.2-3, for cooling components of the device 10 that are heated by the
process
temperature inside the furnace. In the charging device 10, a rotatable
structure,
hereinafter called suspension rotor 14 supports a distribution chute 16. The
distribution chute 16 is attached to the suspension rotor 14 by means of a
mechanism configured for varying the tilt angle of the chute 16 about a
horizontal
axis. The rotary charging device 10 further comprises a stationary housing 18
within which the suspension rotor 14 is supported. The stationary housing 18
comprises a fixed tubular central feed channel 20, which is arranged coaxially
on
the central axis A of the furnace. During the charging procedure, in a manner
known per se, bulk material is fed via the feed channel 20, through the
stationary
housing 18 and the suspension rotor 14, onto the distribution chute 16. The
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distribution chute 16 distributes charge material radially and
circumferentially
inside the furnace according to its inclination and rotation.
[0028] Except for the cooling system 12, the configuration of the charging
device
may be of a well-known type. Various well-known components of the charging
5 device 10, such as drive and gear components, are not shown in FIG.1.
These are
described in more detail e.g. in U.S. patent 3880302. As seen in FIG.1, the
suspension rotor 14 is supported on the stationary housing 18 by means of an
annular bearing 22 so as to be rotatable about axis A. The suspension rotor 14
has an essentially annular configuration with a central passage for bulk
material in
10 prolongation of the central feed channel 20. It comprises a cylindrical
inner wall
portion 24 adjacent the central feed channel 20, a lower flange portion 26 for
supporting the chute 16 and protecting the drive and gear components and an
upper flange portion 28, which is mounted to the bearing 22. The stationary
housing 18 and the suspension rotor 14 constitute the casing of the rotary
charging device 10 that typically forms the top closure on the throat of a
blast
furnace (not shown in FIG.1).
[0029] The cooling system 12 comprises a cooling circuit with a rotary circuit
portion 30 fixed on the suspension rotor 14 and a stationary circuit portion
32,
which is best seen in FIGS.2-3, that remains immobile with the stationary
housing
18. During operation, the rotary circuit portion 30 rotates with the
suspension rotor
14 whereas the stationary circuit portion 32 remains immobile with the housing
18.
The rotary circuit portion 30 comprises any suitable heat exchanger, e.g. a
heat
exchanger comprising several cooling pipe coils, e.g. two coils 34, 36 as
shown in
FIG.1, that are arranged on the suspension rotor 14. The coils 34, 36 are in
thermal contact with the inner wall portion 24 and the lower flange portion
26, on
their inside in order to cool parts of the charging device 10, which are most
exposed to the furnace heat. In addition, the rotary circuit portion 30 also
provides
cooling of the drive and gear components (not shown) provided for rotating and
pivoting the chute 16. Although not shown in FIGS.1-3, the rotary circuit
portion 30
may comprise additional cooling pipes / coils, e.g. for cooling the
distribution chute
16 itself, as disclosed e.g. in U.S. patent 5.252.063, or any other suitable
kind of
heat exchanger configuration.
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[0030] As will be understood, during operation, the cooling system 12 carries
away heat collected by the rotary circuit portion 30 via the stationary
circuit portion
32. To this effect, as seen in FIGS.1-3, the cooling system 12 comprises a
heat
exchanger 38 and a circulation pump 40, which are part of the stationary
circuit
portion 32. As further seen in FIGS.2-3, the stationary circuit portion 32
further
comprises a replenishing valve 42 connecting a replenishing conduit, fed e.g.
by a
public main or local water supply, to the stationary circuit portion 32 for
initial filling
and for topping up. Liquid coolant, especially water, possibly distilled
water, is
preferred, although use of other cooling fluids, including gases is possible.
In the
variant of FIG.3, the stationary circuit portion 32 further comprises a vent
tank 44
for use in combination with the venting device of FIG.9, which allows for
venting
the circuits 30, 32.
[0031] As will be appreciated, the cooling system 12 is configured to achieve
forced circulation of coolant from the stationary circuit portion 32 to the
rotary
circuit portion 30 and vice-versa, while the latter portion 30 rotates
relative to the
former portion 32. To this effect, the cooling system 12 includes an annular
swivel
joint 100, which fluidally couples both circuit portions 30, 32 as
schematically seen
in FIGS1-3. As seen in FIG.1, the annular swivel joint 100 is provided in an
upper
portion of the stationary housing 18, e.g. on the upper flange portion 28 and
underneath the top plate of the housing 18, other locations being possible.
The
swivel joint 100 is of generally annular configuration and arranged coaxially
on
axis A, e.g. so as to surround the feed channel 20 as seen in FIG.1.
[0032] As shown in FIGS.2-3, the fluidal swivel joint 100 according to the
invention comprises a stationary forward connection 102 (stationary inlet),
through
which it receives coolant from the stationary circuit portion 32, and a rotary
forward
connection 104 (rotary inlet), through which it supplies coolant to the rotary
circuit
portion 30. Moreover, the fluidal swivel joint 100 includes a rotary return
connection 106 (rotary outlet), through which it receives coolant from the
rotary
circuit portion 30, and a stationary return connection 108 (rotary outlet),
through
which it returns coolant to the stationary circuit portion 32. Accordingly,
the single
fluidal swivel joint 100 serves as dual coupling in both forward (inlet) and
return
(outlet) directions. As will be understood, the fluidal swivel joint 100 may
comprise
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several pairs of rotary forward and return connections 104, 106, e.g. a pair
for
each separate coil 34, 36 connected in parallel to the fluidal swivel joint
100. For
more equal pressure distribution, the fluidal swivel joint 100 may also
comprise
several pairs of stationary forward and return connections 102, 108 (see
FIGS.5A-
B).
[0033] As seen in FIG.1 and FIG.4 (in which annular curvature is not shown),
the
fluidal swivel joint 100 comprises an annular rotary part 110 that is attached
to the
suspension rotor 14 and an annular fixed part 112 that is attached to the
stationary
housing 18. These rotary and fixed parts 110, 112 have conjugated mating
configurations that allow fully revolving (>360 ) relative rotation. In the
embodiment
of FIGS.1-4, the rotary part 110 includes a generally annular trough 114, i.e.
a
ring-shaped narrow and upwardly open receptacle having the form of a gutter.
Although the trough 114 preferably belongs to the rotary part of the joint
100, with
parts and connections appropriately inverted, the trough could likewise belong
to
the fixed part. The trough 114 delimits an annular volume by means of which
the
circuit portions 30, 32 are in fluidal communication as illustrated in FIG.3.
[0034] As best seen in FIGS.3-4, a main feature of the fluidal swivel joint
100 is
a partition 120 arranged inside the trough 114. More specifically, the
partition 120
is a structure that divides the inner volume of the trough 114 into separated
regions, namely an annular external cavity 122 and an annular internal cavity
124.
In the first embodiment, as best seen in FIG.3, the partition 120 is
configured so
that the return connections 106, 108 communicate, i.e. they are fluidally
coupled,
via the internal cavity 124. Conversely, the forward connections 102, 104
communicate via the external cavity 122. A reversed arrangement of forward and
return connections, as described below in relation to FIGS.5-7 and FIGS.10-11
is
also possible. The partition structure 120 is shaped so that the upper portion
of the
external cavity 122 partially surrounds the internal cavity 124. With its
upper
portion taken together with an optional lower portion, the external cavity 122
fully
surrounds the internal cavity 124. The lower portion serves as an annular
collector
for the rotary forward connection(s) 104 and is therefore optional. Similarly,
the
internal cavity 124 has a certain volume content serving as collector for the
stationary return connection 108.
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[0035] Turning to FIG.4, purely exemplary constructions of the fluidal swivel
joint
100 and of the partition structure 120 will be detailed below. The trough 114
is of
generally rectangular U-shaped cross-section and made e.g. of profiled metal
sheet sectors, whereas it may also be formed in part by the suspension rotor
14
5 itself. The fixed part 112, as a main component, comprises an annular
hood 126,
which is of generally rectangular inverted U-shaped cross-section and also
made
e.g. of profiled metal sheet sectors. The annular hood 126 is mounted on the
stationary housing 18 and protrudes into the trough 114. The rotary trough 114
and the stationary hood 126 each respectively have vertical inner and outer
10 sidewalls 134, 136. The sidewalls 134, 136 are separated by narrow
vertical gaps
138, the width of which slightly exceeds the radial tolerance of the bearing
22. The
orientation of the gaps 138 may also be slanting, e.g. in V-shape. The upper
portion of both sidewalls 136 of the hood 126 is recurved around the upper end
of
the sidewalls 134 of the trough 114 in order to provide a chicane or labyrinth-
like
15 seal that reduces exposure of the gaps 138 to the dust-laden atmosphere
from
inside the housing 18. To the same effect, the sidewalls 134 of the trough 114
are
provided with swellings 137. In order to substantially eliminate exposure to
dust,
the hood 126 is further provided at the upper recurved end of each sidewall
136
with circumferentially distributed injection pipes 139 connected to an
appropriate
gas supply. The injection pipes 139 are operated to inject inert gas, e.g. N2,
at a
pressure that slightly exceeds the pressure inside the housing 18 in order to
displace the dust-laden atmosphere out of the gaps 138. The partition 120 on
the
other hand consists of a ring-shaped rotary partition member 140 and a
cooperating ring-shaped stationary partition member 142. The stationary
partition
member 142 has a cross-section with a II-shaped (greek "Pi", capital letter)
concave central part and horizontal lateral disk flanges on either one side.
Furthermore, the annular stationary partition member 142 is provided with
interrupted circular arc-shaped apertures 144 arranged circumferentially in
each
lateral end portion of the horizontal flanges. At its extremities, the
partition member
142 is fixed to the lower ends of the sidewalls 136 of the hood 126. The
annular
partition member 142 can be assembled of correspondingly shaped sectors of
punched and profiled sheet metal. The rotary partition member 140 of FIGS.1-4
is
a simple ring-shaped plate having interrupted circular arc-shaped apertures
146
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arranged circumferentially in its radially inward and outward end regions so
as to
face the apertures 144. The rotary partition member 140 is fixed at its
extremities
to the sidewalls 134 of the trough 114 at a certain height inside the trough
114. As
will be understood, each pair of facing apertures 144, 146 warrants
unrestrained
free communication between the upper and lower portions of the external cavity
122 and thus between the forward connections 102, 104. The partition members
140, 142 are spaced by a vertical distance that slightly exceeds the axial
tolerance
of the bearing 22.
[0036] In order to allow unimpeded relative rotation between the fixed part
112
and the rotary part 110, the joint 100 has an annular first clearance 150 and
an
annular second clearance 152 provided between the partitioning members 140,
142. Due to this required clearance, the external cavity 122 and the internal
cavity
124 are necessarily in leakage permitting communication. As will be
appreciated
however, the partition 120 is configured to provide a double and substantially
symmetrical communication through both clearances 150, 152. To this effect,
the
stationary and rotary partition members 140, 142 are configured mirror-
symmetric,
i.e. left-right symmetric, with respect to an imaginary vertical bisecting
axis of the
joint 100 (see dashed line in FIGS.6A-D) in general and of the annular trough
114
in particular. Similarly, the trough 114 and the hood 126 are both generally
mirror-
symmetric. Thereby, despite leakage between the cavities 122, 124, largely
spatially uniform, left-right symmetrical pressure conditions exist inside the
external cavity 122. As a result, essentially equal water levels are warranted
inside
the gaps 138, which both communicate freely with each other through the
external
cavity 122. The crosswise width of the clearances 150, 152 corresponds to the
spacing between the partition members 140, 142, i.e. a distance that slightly
exceeds the axial tolerance of the bearing 22. As may also be noted, the width
of
the apertures 146 in the rotary partition member 140 is preferably larger than
the
crosswise width of the clearances 150, 152, whereas the width of the apertures
144 in the stationary partition member merely needs to warrant free
communication between the upper and lower portions of the external cavity 122.
[0037] In order to enable forced circulation of coolant through the rotary
circuit
portion 30, e.g. through the coils 34, 36, by action of the stationary pump
40,
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short-circuiting of coolant flow through the clearances 150, 152 should be
minimized. To this purpose, annular first and second flow restrictors 160, 162
are
provided in the first and second clearances 150, 152 respectively. The flow
restrictors 160, 162 are configured to minimize leakage between the external
and
internal cavities 122, 124, i.e. to minimize short-circuiting of the coolant
flow
through the clearances 150, 152. In other words, since the clearances 150, 152
physically form "parasitic conduits" connected in parallel to the rotary
circuit portion
30, the flow restrictors 160, 162 are provided to significantly increase the
flow
resistance of these undesired parallel "parasitic conduits". Preferred flow
restrictors 160, 162 are non-contact labyrinth seals formed e.g. by conjugated
protrusions and/or recesses on both or either one of the facing portions of
the
partition members 140, 142 that form the clearances 150, 152. A major
advantage
of this type of flow restrictor 160, 162 is that they do not wear off.
[0038] Returning to FIG.3, an arrangement for controlling the coolant level
inside
the fluidal swivel joint 100 comprises a level sensor 50, schematically
illustrated in
FIG.3. The level sensor 50 is arranged in one of the gaps 138 (FIG.4) and used
to
detect whether the coolant falls below the minimum level, indicated at 51.
When
the minimum level 51 is reached, the level sensor 50, e.g. by use of a
controller of
suitable known configuration (not shown), triggers opening of the motorized
replenishing valve 42 for topping up a loss of coolant, typically caused by
evaporation. The level sensor 50 also detects reaching of the maximum level,
indicated at 53, in order to trigger closing of the replenishing valve 42. The
maximum level 53 is set above the top plate of the hood 126 so that, during
normal operation, the external cavity 122 is substantially filled with
coolant.
FIGS.2-3 further show a venting device 60, which will be described below with
reference to FIG.9.
[0039] A second embodiment of an annular swivel joint 200 will now be
described by reference to FIGS.5-7. Main features being identical to those of
the
previous embodiment, only the differences will be set out below. The plan
views of
FIG.5A and FIG.5B best illustrate the annular configuration (which applies
analogously to FIGS.1-4) of the swivel joint 200.
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[0040] As seen in FIG.5A, illustrating the fixed part 212 in top view, the
fluidal
swivel joint 200 comprises four stationary forward connections 202 and four
stationary return connections 208, which respectively connect forward
(supply/flow) and return (runback) manifolds (not shown) of the stationary
circuit
portion 32 to the joint 200. The stationary connections 202, 208 are arranged
equi-
circumferentially and centrally in the radial sense for maintaining
circumferentially
uniform pressure conditions within the generally left-right symmetric joint
200.
[0041] FIG.5B illustrates the rotary part 210 in bottom view. As seen in
FIG.5B,
the fluidal swivel joint 200 is configured for supplying two parallel parts of
the
rotary circuit portion 30, e.g. two cooling pipe coils 34, 36 as illustrated
in FIG.1.
Accordingly, the joint 200 comprises two pairs of diametrically opposite
rotary
forward connections 204 and rotary return connections 206.
[0042] In FIGS.6A-6D only main reference signs are provided for alleviation of
the drawings. As seen in FIGS.6A-6D and as opposed to FIGS.1-4, in the swivel
joint 200, the forward connections 202, 204 are coupled through the internal
cavity
224, i.e. on the inside of the partition structure 220, whereas the return
connections 206, 208 are coupled through the external cavity 222, i.e. on the
outside of the partition 220. More specifically: As shown in FIG.6A, the
stationary
forward connections 202 debouch into the internal cavity 224 at the upper
plate in
the II-shaped central portion of the stationary partition member 242. As seen
in
FIG.6C, the rotary forward connections 204 spring from the internal cavity 224
at
the central part of the rotary partition member 240 that forms a lower plate.
On the
other hand, concerning the return connections 206, 208, the rotary return
connections 206 debouch into the lower portion of the external cavity 222 at
the
bottom plate of the trough-shaped rotary part 210, whereas the stationary
return
connections 208 spring from the upper portion of the external cavity 222 at
the top
plate of the hood-shaped rotary part 212. A configuration according to FIGS.1-
4, in
which the forward path passes through the external cavity 122 and the return
path
passes through the internal cavity 124, maximizes the volume of coolant that
may
evaporate and thus minimize the frequency of replenishing through replenishing
valve 42. The connection scheme and circulation sense of FIGS.5-7 however
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enables integrating a simpler self-venting solution into the swivel joint 200,
which
will be detailed below with respect to FIGS.10-11.
[0043] As further seen in FIGS.6A-D and FIG.7, the fluidal swivel joint 200
comprises first and second annular gas distributor pipes 270, 272 connected to
a
suitable supply of gas, especially of inert gas such as N2. Each gas
distributor pipe
270, 272 is respectively associated to one annular clearance 250, 252. Each
gas
distributor pipe 270, 272 is provided equi-circumferentially with injector
nozzles or
simple bores that communicate through a corresponding hole or bore in the
stationary partition member 242 with the associated clearance 250, 252 for
injecting a bubbling gas, into the liquid coolant on the forward (upstream)
side of
the clearances 250, 252. With the higher forward coolant pressure in the
internal
cavity 224, each distributor pipe 270, 272 thus injects gas for bubbling the
coolant
on the upstream side of the flow restrictors 260, 262. By virtue of the
resulting
effervescence, the flow resistance created by the labyrinth seal-type flow
restrictors
260, 262 is further enhanced. As seen in FIGS.6A-D, the configuration of the
gas
distributor pipes 270, 272 is symmetrical in order to equally enhance the
effectiveness of both flow restrictors 260, 262. As will further be
appreciated, the
bubbling gas injection through the distributor pipes 270, 272 also assumes the
function of creating a displacement pressure inside the vertical gaps 238
between
the fixed part 212 and the rotary part 210 to avoid dust contamination. To
this
effect, the downstream end of each clearance 250, 252 debouches directly into
the
corresponding gap 238. In order to avoid inclusion of gas bubbles in the
coolant
that returns through the external cavity 222, the communication between the
upper
and lower portions of the external cavity 222 is established through
horizontal
apertures 244 arranged in the horizontal sidewalls of the hood 226, as best
seen
in FIG.7. The horizontal apertures 244 enable general venting of the circuits
30, 32
and venting of inclusions of bubbling gas injected via the distributor pipes
270,
272, since gases tend to rise upwards through the gaps 238, which act as
annular
uptakes communicating with the ambient atmosphere. Accordingly, the upper and
lower portions of the external cavity 222 communicating freely trough the gaps
238
and apertures 244, bubbling gas rises upwards in the gaps 238 and is only
minimally included in the return flow from the external cavity 222 to the
stationary
circuit portion 32.
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[0044] In the perspective view of FIG.7, the illustrated fluidal swivel
joint 200 is
provided with additional reference sings with an incremented hundreds digit
compared to FIG.4, which identify features that are identical or similar to
those
described above in relation to FIG.4. FIG.7 further illustrates respective
feed pipes
5 274, 276 of the gas distributor pipe 270, 272, which feed inert gas for
injection into
the clearances 250, 252.
[0045] FIG.8 illustrates the fluidal swivel joint 100 of FIGS.1-4
equipped with a
first embodiment of a venting device 59. The venting device 59 is a venting
valve
of the float valve type and is arranged in the top plate of the hood-shaped
fixed
10 part 112 so as to vent the upper portion of the external cavity 122 in
case the
coolant level drops below a predetermined level, e.g. a venting level 56 as
indicated in FIG.8.
[0046] FIG.9 illustrates the fluidal swivel joint 100 of FIGS.1-4
equipped with a
second embodiment of a venting device 60. The venting device 60 is designed in
15 particular for venting residual air and vapour locked in the circuits
30, 32. It
comprises a small-diameter venting pipe 61 bridging the uppermost region of
the
external cavity 122 to the stationary return connection 208 and a ventilating
valve
63 provided in the venting pipe 61 for adjusting the venting rate of
gas/vapour. The
ventilating valve 63 allows only a minimal amount of liquid coolant to pass
through
20 the venting pipe 61 into the return connection 208. Due to the draught
caused by
forced circulation, gases in the external cavity 122 are automatically
evacuated
through the return connection 208, and may then be de-aerated by means of an
auxiliary venting device 65 provided on the vent tank 44 (see FIG.3), in which
residual air and vapour bubbles up.
[0047] Referring now to FIGS.10-11, a preferred third embodiment of a fluidal
swivel joint 300 will be described below.
[0048] In the joint 300 of FIGS.10-11, the rotary part 310 comprises an
annular
trough 314 of substantially rectangular U-shaped cross-section that is formed,
on
one side, by the upper part of the cylindrical inner wall portion 24 of the
suspension rotor 14, and on the other side, by a cylindrical ring 313 fixed to
the
wall portion 24 by means of a disc-shaped bottom plate 315. The fixed part 312
comprises an annular hood 326, of inverted substantially rectangular U-shaped
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cross-section, which protrudes approximately halfway into the annular volume
defined by the annular trough 314. The trough 314 and the hood 326 are
dimensioned so that narrow vertical gaps 338 between the sidewalls 24, 313 of
the
trough 314 and the sidewalls 336 of the hood 326 have minimal width required
for
unimpeded rotation of the trough 314 relative to the hood 326. As seen in
FIGS.10-11, the upper end portions of the sidewalls 24, 313 of the trough 314
protrude into conjugated recesses provided in the top plate of the stationary
housing 18 so as to form a chicane or labyrinth-like joint reducing exposure
of the
gaps 338 to dust.
[0049] As best illustrated in FIG.11, the fluidal swivel joint 300 also
comprises a
partition structure 320 that divides the inner volume of the trough 314 into
an
annular external cavity 322 and an annular internal cavity 324. The stationary
partition member 342 of the partition 320 mainly consists of two annular
downwardly tapering machined parts 342-1, 342-2 fixed to a disc-shaped upper
plate 342-3. Similarly, the rotary partition member 340 mainly consists of two
annular upwardly tapering machined parts 340-1, 340-2 fixed to a lower disc-
shaped plate 340-3. The stationary partition member 342 is fixed to the
stationary
housing 18, whereas the rotary partition member 340 is fixed to the wall
portion 24
of the suspension rotor. As will be appreciated, both partition members 340,
342,
as well as the trough 314 and the hood 326 are generally left-right
symmetrical in
cross-section.
[0050] Each stationary machined part 342-1, 342-2 defines a respective oblique
inner labyrinth surface 343 facing a respective conjugated oblique outer
labyrinth
surface 345 defined by either one of the rotary machined parts 340-1, 340-2.
The
annular surfaces 343, 345 may be simple stepped surfaces, simple corrugated
surfaces or surfaces with alternating protrusions and recesses that are
arranged to
interdigitate, similar to the labyrinth seal disclosed in FIG.4-5 of WO
99/28510.
Between the surfaces 343, 345, the rotary and stationary partition members
340,
342 define annular clearances 350, 352 of minimal width as required to permit
rotation. As will be understood, the external and internal cavities 322, 324
communicate through these clearances 350, 352. Accordingly, similar to the
previous embodiments, the labyrinth surfaces 343, 345 form flow restrictors
360,
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362 in each clearance 350, 352 respectively in order to minimize short-
circuiting
flow between the cavities 322, 324.
[0051] As seen in FIGS.10-11, the rotary partition member 340 is shaped and
arranged to protrude into the stationary partition member 342 with the
labyrinth
surfaces 343, 345 facing each other so that the clearances 350, 352 form
branches of a generally inverted V-shape in cross-section. This oblique
arrangement allows increasing the length of the flow restrictors 360, 362 i.e.
the
non-contact labyrinth seals defined by the surfaces 343, 345, without
increasing
the overall height/width of the partition 320. As will be appreciated, in the
joint 300,
the flow restrictors 360, 362 extend substantially over the entire length of
the
oblique clearances 350, 352, which exceeds the height (greatest sectional
dimension) of the internal cavity 324, in order to maximize achieved flow
resistance / pressure drop.
[0052] As further seen in FIGS.10-11, the upper and lower portions of the
external cavity 322 communicate unrestrictedly through annular vertical
channels
348 between the cylindrical outer surfaces of the stationary machined parts
342-1,
342-2 and the sidewalls 336 of the hood 326 and via the lower portions of the
vertical gaps 338 into which the channels 348 debouch through transversely,
e.g.
horizontally, arranged apertures 344. Accordingly, any general gas inclusions,
including optionally gas injected by optional gas bubbling upstream of the
clearances 350, 352, can be largely prevented from entering the upper portion
of
the external cavity 322, i.e. from entering the return path through the
stationary
return connection 308.
[0053] Venting works in substantially identical manner as in swivel joint 200
of
FIGS.5-7: Any included gas preferentially passes by the apertures 344 and
rises
upwardly through the upper portion of the gaps 338 to be vented to the
atmosphere, e.g. to the inside of housing 18. Returning coolant, on the other
hand,
is forced from the lower portion of the external cavity 322, through the lower
portion of the gaps 338, to turn laterally through the horizontal apertures
344 into
the channels 348 to pass into the upper portion of the external cavity 322.
Accordingly, by virtue of the horizontally arranged apertures 344 and the
chosen
flow sense, i.e. the return flow passing upwardly through the external cavity
322,
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the swivel joint 300 has an integrated self-venting configuration, venting
air/gas
through the inherent gaps 338. An advantage of the self-venting solutions of
FIGS.5-7 and FIGS.10-11, resides in that a vent tank arrangement as in FIG.3
and
venting devices as in FIGS.8-9 can be omitted so that a simpler cooling
circuit 12
as in FIG.2 can be used. As will be understood, proper venting of residual air
and
vapour locked in the coolant enables complete filling of the circuit portions
30, 32
and warrants uninterrupted forced circulation through the rotary and
stationary
circuit portions 30, 32 by action of pump 40.
[0054] FIG.10 also illustrates the minimum and maximum water levels 351, 353,
between which coolant is maintained during normal operation by means of an
appropriate level detection device that controls replenishing via the
replenishing
valve 42 (see FIG.2) to avoid suction of ambient air into the return
connection 308
and overflow of coolant out of the gaps 338.
[0055] In operation, the fluidal swivel joint 300 works as follows:
[0056] As illustrated in FIG.10, cooled liquid coolant is supplied under
pressure
by the pump 40 from the stationary circuit portion 32 through the stationary
forward connection 302 into the internal cavity 324. To this effect, the
stationary
forward connection 302 passes trough the upper plate 342-3 of the stationary
partition member 342. From the pressurized internal cavity 324, most of the
coolant is supplied to the "forward side" of the rotary circuit portion 30,
e.g. to a coil
34, 36, through the rotary forward connection 304 (only incidentally located
in the
same plane as the stationary forward connection 302 in the position shown in
FIG.10). To communicate with the internal cavity 324, the rotary forward
connection 304 passes trough the lower plate 340-3 of the rotary partition
member
340. Accordingly the rotary circuit portion 30 is provided with pressurized
coolant,
i.e. subjected to forced circulation through the fluidal swivel joint 300.
Short-
circuiting coolant flow through the clearances 350, 352 on the other hand is
minimized by the facing pairs of surfaces 343, 345 which form a labyrinth
seal.
[0057] As best illustrated in FIG.11, heated liquid coolant that has absorbed
heat, e.g. at one of several coils 34, 36, is returned from the rotary circuit
portion
30 via the rotary return connection 306, which debouches into the lower
portion of
the external cavity 322 through a central bore in the bottom plate 315. From
there,
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coolant is forced upwardly through a lower region of the gaps 338, laterally
into
and upwardly through the annular vertical channels 348, into the upper portion
of
the external cavity 322. From there, liquid coolant passes via the stationary
return
connection 308, which takes source in the upper portion of the external cavity
322
through a central bore in the disc-shaped top plate 327 of the annular hood
326,
back to the return side of the stationary circuit portion 32.
[0058] As will be understood, operation of the fluidal swivel joint 200 of
FIGS.5-7
is substantially identical, whereas operation of the fluidal swivel joint 100
of
FIGS.1-4 differs mainly in the inverted forward and return connections 102,
104;
106, 108 and therewith the opposite coolant circulation sense and, moreover in
the
manner by which the circuits 30, 32 are vented.
[0059] Referring now to FIG.12, a most preferred fourth embodiment of a swivel
joint 400 will be described. The swivel joint 400 of FIG.12, whereas it
provides the
same benefits as the embodiment of FIGS.10-11, is more cost-efficient in
manufacture and considered more reliable.
[0060] As will be appreciated, the rotational position illustrated in FIG.12
corresponds to that illustrated in FIG.10, i.e. a position where the section
lines A-A
and C-C of FIGS.5A-B would coincide. Accordingly, in FIG.12, a stationary
forward
connection 402 and a rotary forward connection 404 are shown in axially
aligned
position. The rotary part 410 also comprises an annular U-shaped trough 414
into
which an annular U-shaped hood 426 of the fixed part 412 similarly protrudes
downwards. Between the sidewalls of the hood 426 and of the trough 414 there
are similar but longer respective narrow gaps 438 that permit venting and
unimpeded rotation. Venting is favored by downwardly slanting apertures 444,
through which an upper portion of the external cavity 422 communicates with a
lower portion thereof. The apertures 444 are provided in the lowermost region
of
the sidewalls of the hood 426 and define the minimum operational water level.
Even though not shown in FIG.12, it will be understood, that the stationary
and
rotary return connections are provided similarly as in FIG.11, i.e. in the
bottom
plate 415 of the trough 414 and in the top cover of the stationary housing 18
respectively. Accordingly, as illustrated in FIG.12, the forward path passes
through
the internal cavity 424, whereas the return path (not shown) passes through
the
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H8312532CA
external cavity 422. As in the previous embodiments, the rotary part 410 and
the
stationary part 412 have a generally mirror-symmetric configuration.
[0061] As will be noted when compared to FIGS.10-11, the embodiment of
FIG.12 mainly differs in terms of the structure of the partition structure 420
and, in
s particular, the configuration of its rotary and stationary partition
members 440, 442
and, consequently, of the first and second flow restrictors 460, 462 there
between.
[0062] As seen in FIG.12, the stationary partition member 442 comprises a
= hood-shaped ring assembly of inverted U-shaped cross-section that is
arranged
inside the hood 426. The hood-shaped ring assembly has a radially inner side
442-1, a radially outer side 442-2 and an upper plate 442-3 and can be build
in
simple manner, e.g. as a welded steel plate assembly. Similar to FIGS.10-11,
vertical channels 448 are provided between the sidewalls of the hood 426 and
the
inner and outer sides 442-1, 442-2 of the stationary partition member 442 in
order
to connect the upper and lower portions of the external cavity 422.
Accordingly,
the channels 448 form part of the external cavity 422 so that the external
cavity
422 surrounds the internal cavity 424. In the embodiment of FIG.12, the length
of
the channels 448 is increased however to increase the filling level.
[0063] The rotary partition 440 on the other hand comprises a plurality of
vertically stacked Teflon rings 441 that protrude into the ring assembly of
the
stationary partition member 442. A single ring of increased height is also
possible,
whereas a certain minimum height is desired in order to achieve sufficient
flow
restriction (pressure drop). In the embodiment of FIG.12, the Teflon rings
441
have a truncated wedge shaped cross-section that widens downwards, i.e. the
rings have a radially inner face 441-1 and a radially outer face 441-2 that
are
oblique. Alternatively or in combination, the faces of the Teflon rings 441
can be
corrugated. Each face 441-1, 441-2 is arranged with a small radial clearance,
in
the order of several tenths of a millimetre wide, adjacent the corresponding
adjacent side 442-1, 442-2 of the stationary ring assembly 442, i.e. with the
required first and second clearances 450, 452 there between in order to permit
relative rotation. As will be appreciated, by virtue of the configuration of
the
Teflon rings 441, turbulence is created within the leakage-permitting
clearances
450, 452. Accordingly, the faces 441-1, 441-2 in cooperation with the closely
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H8312532CA
adjacent inner and outer sides 442-1, 442-2 of the stationary partition member
442
respectively form first and second flow restrictors 460, 462 of the labyrinth
seal
type. Teflon 0 is preferred as material for the rings 441 since it has so-to-
speak
"self-lubricating" properties in case of accidental contact between the rotary
and
stationary partition members 440, 442. The rings 441 can by made one-piece and
configured fully circumferential with corresponding bores for receiving tubes
of the
rotary forward connections 404 as seen in FIG.12.
[0064] As will be understood, despite an improved structure, operation of the
swivel joint 400 of FIG.12 is generally identical to that of FIGS.10-11 as
described
hereinbefore.
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List of reference signs:
FIG.1-FIG.4 137 swellings
rotary charging device 138 gaps
12 cooling system 139 injection pipes
14 suspension rotor 140 rotary partition member
16 distribution chute 142 stationary partition member
18 stationary housing 144, vertical apertures
feed channel 146
22 annular bearing 150 annular first clearance
24 inner wall portion 152 annular second clearance
26 lower flange portion 160 first flow restrictor
28 upper flange portion 162 second flow restrictor
rotary circuit portion FIG.5A-FIG.7
32 stationary circuit portion 200 annular swivel joint
34, 36 cooling pipe coils 202 stationary forward connection
38 heat exchanger 204 rotary forward connection
circulation pump 206 rotary return connection
42 replenishing valve 208 stationary return connection
44 vent tank 210 rotary part
level sensor 212 fixed part
51 minimum level 214 (rotary) annular trough
53 maximum level 220 partition
venting device 222 external cavity
auxiliary venting device 224 internal cavity
100 annular swivel joint 226 (stationary) annular hood
102 stationary forward connection 234, sidewalls
236
104 rotary forward connection 237 swellings
106 rotary return connection
238 gaps
108 stationary return connection
240 rotary partition member
110 rotary part 242 stationary partition member
112 fixed part 244 horizontal apertures
114 (rotary) annular trough
250 annular first clearance
120 partition
252 annular second clearance
122 external cavity
260 first flow restrictor
124 internal cavity 262 second flow restrictor
126 (stationary) annular hood 270, bubbling gas distributor pipes
134, sidewalls 272
136
CA 02770250 2016-07-04
28
H8312532CA
274, gas distributor feed pipes
276 344 transverse apertures
FIG.8 348 vertical channels
350 annular first
clearance
56 venting level
351 minimum coolant level
59 venting device
FIG.9 352 annular second
clearance
353 maximum coolant level
60 venting device
360 first flow restrictor
61 venting pipe
362 second flow
restrictor
63 ventilating valve
FIG.10-FIG.11 FIG.12
400 annular swivel joint
300 annular swivel joint
402 stationary forward
connection
302 stationary forward connection
404 rotary forward
connection
304 rotary forward connection
410 rotary part
306 rotary return connection
412 fixed part
308 stationary return connection '
414 (rotary) annular
trough
310 rotary part
312 fixed part 415 bottom plate
420 partition
313 cylindrical ring
422 external cavity
314 (rotary) annular trough
424 internal cavity
315 bottom plate
320 partition 426 (stationary) annular
hood
438 gaps
322 external cavity
440 rotary partition
member
324 internal cavity
326 (stationary) annular hood 441 Teflon() rings
441-1 inner face
327 top plate
336 sidewalls 441-2 outer face
337 swellings 442 stationary partition
member
442-1
338 gaps inner side
340 rotary partition member 442-2 outer side
340-1, tapering machined parts 442-3 upper plate
340-2 444 transverse apertures
340-3 lower plate . 445 labyrinth surfaces
342 stationary partition member 448 vertical channels
342-1, tapering machined parts 450 annular first
clearance
342-2 452 annular second
clearance
342-3 upper plate 460 first flow restrictor
343, labyrinth surfaces 462 second flow
restrictor
345
